Haley DB, Rushen J, Duncan IJH, Widowski TM
Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada
Anim Behav. 1998 Dec;56(6):1545-1551. doi: 10.1006/anbe.1998.0912.
During nursing, the young of many ungulates butt at their dams' udder, which has been hypothesized to reflect difficulty obtaining milk. We investigated the effect of manipulating milk flow rate on the butting behaviour of domestic calves sucking milk from an artificial teat. The lowest rate of butting during nutritive sucking occurred with the fastest flow rate, and the highest rate of butting occurred with the slowest flow rate. When milk flow rate was changed during a meal, calves butted more following a decrease in flow rate than following an increase in flow rate. Butting rates were consistent and relatively low with a constant flow of milk. Regardless of flow rate, calves butted more at the beginning of their meal compared with the middle and end. Overall, the highest butting rate occurred when milk flow stopped, either at the end of the meal or when milk flow during the meal was stopped repeatedly for 30-s periods. We conclude that calves are sensitive to variations in milk flow rate and that butting rate changes accordingly. The occurrence of butting by young ungulates during nursing thus may indicate either a stoppage of milk flow or a decrease in milk flow rate, and thus may help identify periods of nonnutritive sucking during nursing. (c) 1998 The Association for the Study of Animal Behaviour.
在哺乳期间，许多有蹄类动物的幼崽会顶撞其母兽的乳房，据推测这反映了获取乳汁的困难。我们研究了控制乳汁流速对从人工乳头吸吮乳汁的家牛犊顶撞行为的影响。在营养性吸吮过程中，顶撞发生率最低的是流速最快时，而顶撞发生率最高的是流速最慢时。当在一餐中改变乳汁流速时，犊牛在流速降低后比在流速增加后顶撞得更多。当乳汁流速恒定时，顶撞发生率稳定且相对较低。无论流速如何，犊牛在一餐开始时比在中间和结尾时顶撞得更多。总体而言，顶撞发生率最高的时候是乳汁流动停止时，要么是在一餐结束时，要么是在一餐期间乳汁流动被反复停止30秒的时候。我们得出结论，犊牛对乳汁流速的变化很敏感，并且顶撞发生率会相应改变。因此，有蹄类动物幼崽在哺乳期间的顶撞行为可能表明乳汁流动停止或流速降低，从而可能有助于识别哺乳期间的非营养性吸吮时段。（c）1998年动物行为研究协会。
